Nickel anode



Patented May 17, 1938 UNITED STATES NICKEL ANODE Clarence G. Bieber andMortimer P. Buck, Huntlngton, W. Va... usignors to The InternationalNickel Company, Inc., New York, N. Y., a corporation of Delaware NoDrawing. Application July 11, 1936, Serial No. 90.178. Renewed June 18,1937 11 Claims.

The present invention relates to nickel anodes forthe electrodepositionof nickel and particularly to rolled nickel anodes containing carbon.

The art of nickel plating has been confronted with problems due to thephysical, chemical, metallurgical and electrical properties of nickelanodes almost from the inception of the industry. Anodes of electrolyticnickel having a nickel content of 97% or better develop a passivity veryo shortly after the electrolysis has started. This passivity results indecreased anode current efflciency. As a means of eliminating thispassivity the use of alloy anodes containing iron and carbon has beensuggested. However, these have not been entirely successful since alloyanodes containing 6% iron tend to discolor the nickel plating depositedon the cathode. To obviate this difliculty anodes containing less than1% iron and made of 95-97% nickel bearing carbon were introduced. Suchanodes have many defects. Among the disabilities from which such castnickel carbon bearing anodes suffer are cracks, blow-holes and othermechanical defects. In addition, the anode has a coarsely grainedstructure. To these imperfections may be ascribed the well-knowncharacteristic of cast nickel carbon-bearing anodes to slufi oil largequantities of undissolved nickel. In fact some experts attribute all thedefects of cast nickel anodes to the presence of carbon. These anodeshave tended to corrode very unevenly. The tendency to slufl offundissolved nickel may not seem to be of much importance butinvestigation has shown that as much as 27% of the nickel removed fromthe anodes in the course of an ordinary plating operation wasundissolved nickel.

This undissolved nickel has represented a loss of nickel which must bethrown away or recovered at an additional expense. Furthermore, this un-40 dissolved nickel frequently has been deposited on the cathode orarticle being plated to the detriment of the finish of the platedarticle. The imperfect or defective articles spoiled as describedhereinbefore constitute a serious economic loss and a disturbance in asystem of production. Such cast nickel anodes have been known toseparate in service and to cause large portions to drop to the bottom ofthe tank and mix with the sludge. Naturally, such cast anodes 5 cannotbe readily worked to form shapes other than those in which they havebeen cast. Rolled carbon-bearing nickel anodes of good corroding qualityhave been offered to the industry but were unsuccessful since theysuffer from an im- 55 portant drawback. Such anodes do not corrodesatisfactorily at pH values above about 4.0 to about 4.5. Thus there hasbeen a pressing need in the nickel plating industry for a highly solublerolled anode containing carbon. Although many attempts and proposalshave been made none, so

far as we are aware, has been wholly successful when carried intopractice on an industrial scale for commercial production.

We have discovered means of avoiding all of the aforesaid disabilitiesof carbon-bearing nickel anodes.

It is an object of the invention to provide a carbon-bearing nickelanode from which a negligible amount or a minimum amount of undissolvednickel sluifs off.

It is another object of the invention to provide a carbon-bearing nickelanode which operates satisfactorily at all pH values including those inexcess of a pH of 4.0 and below a pH of 6.5.

It is a further object of the invention to provide a carbon-bearingnickel anode which operates at an acceptable current efilciency and doesnot become passive.

The invention also contemplates providing ductile carbon-bearing rollednickel anodes.

Other objects and advantages of the invention will become apparent fromthe following descriptlon.

Generally stated, our invention provides for the casting of nickelanodes containing carbon, magnesium, titanium, silicon, iron, copper,cobalt and manganese in critical percentages. Such anodes can be rolledto produce a dense, fine grained structure substantially free fromcracks, blowholes and mechanical defects. Due to the duetility of theseanodes, they may be bent and formed without breaking. Our improved,rolled or cast, carbon-bearing nickel anode corrodes evenly and well atpH values of the order of pH 6 in plating baths at temperatures rangingfrom ordinary room temperature to about 160 F. Our improved rolledanodes operate at a current density of from 1 to 100 amperes per squarefoot with an efficiency of slightly less than 100%. A distinguishingcharacteristic of our improved cast and/or rolled anodes is theformation of a gelatinous, adherent layer on the surface of the anodewhile in operation which traps substantially all theloose undissolvednickel particles and which acts as a strong, tenacious and permeablefilm.

Our improved nickel anode may contain carbon, magnesium, titanium,silicon in the following amounts:

Carbon 0.05-2.0% Magnesium 0.05-1.0% Titanium 0.05-1.0% Silicon 0.051.0%Cobalt Up to 0.50% Iron Up to 0.25% Copper Up to 0.25% Manganese -1 Upto 0.25% Nickel Balance It is preferred that there is not more than amaximum 010.50% cobalt nor more than a maximum of 0.25% of any of thegroup consisting of iron, copper and manganese. In practice, we preferto use a carbon-bearing nickel anode having the following composition:

messes;

balance The improved carbon-bearing nickel anodes operate in hot Wattsplating solution at temperatures from about 110 to about 160 F. at pHvalues of from about pH 1.0 to 6.2 or at ordinary room temperature. Acold solution operates at from about 60 to about 100 F. at pH values upto about pH 6.3 to 6.5. Although the Watts solution has been used astypical of nickel plating solutions the anodes work equally well in theother commercial plating solutions.

For the pu pose of giving those skilled in art a better understanding ofthe invention the following illustrative examples are given.

" Our improved cast and/or rolled carbon-bearing nickel anode has thefollowing composition:

Rolled Cast Percent Percent Balance Balance Although the presentinvention has been described in connection with a preferred composition,it is to be understood that variations and modifications maybe resortedto as those skilled in the art will readily understand. Such variationsand modifications are considered to be within the purview and scope ofthe appended claims.

We claim: v

1. A cast carbon bearing nickel anode comprising carbon about 1.00%,magnesium and titanium about 0.25 to 0.28% of each, silicon about 0.55%,cobalt about 0.35%, iron about 0.14%, copper about 0.10%, manganeseabout 0.12% and the balance nickel.

21$ cast carbon bearing nickel anode comprisl carbon about 0.25 to about1.25%, magnesium about 0.20 to about 0.30%, titanium about 0.15 to about0.25%, silicon about 0.40 to 0.70%, cobalt about 0.30 to about 0.40%,iron about .10 to about 0.20%, copper about 0.05 to about 0.15%,manganese about 0.05 to about 0.15% and the balance nickel.

3. A cast and rolled carbon bearing nickel anode comprising carbon about0.05 to about 2.00%, magnesium about 0.05 to about 1.0%. titanium about0.05 to about 1.0%, silicon about 0.05 to about 1.0%, cobalt up to about0.50%, iron up to about 0.25%, copper up to about 0.25%, manganese up toabout 0.25% and the balance nickel.

4. A rolled carbon bearing nickel anode comprising carbon and magnesiumabout 0.30% of each, titanium about 0.25%, silicon about 0.55%, cobaltabout 0.35%, iron about 0.14%, copper about 0.08%, manganese about 0.12%and the balance nickel.

5. A cast and rolled carbon bearing nickel anode comprising silicon,titanium and magnesium not more than about 1.0% of each, carbon not morethan about twice the silicon content, cobalt not more than about 0.5%,iron, copper and manganese not more than 0.25% of eac and the balancenickel. p

6. A cast and rolled carbon bearing nickel anode comprising about 0.05to about 2.00% carbon, about 0.05 to about 1.0% magnesium, about 0.05 toabout 1.0% titanium, about 0.05 to about 1.0% silicon, upwards to 0.50%cobalt, iron, copper and manganese up to about 0.25% of each and thebalance nickel.

7. A rolled carbon bearing nickel anode comprising carbon and siliconless than about 1.0% of each, magnesium, titanium and cobalt less thanabout 0.50% of each iron, copper and manganese less than about 0.25% oieach and the balance nickel.

8. A cast carbon bearing nickel anode comprising carbon and silicon notmore than about 1.0% of each, magnesium, titanium and cobalt not morethan about 0.50% of each, iron, copper and manganese not more than about0.25% of each and the balance nickel.

9. A cast and rolled carbon bearing nickel anode comprising magnesium,titanium and silicon not more than about 1.0% of each, carbon not morethan about 2.0%, not more than about 0.50% of cobalt, not more thanabout 0.25% of each of the group consisting of iron, copper andmanganese and the balance nickel.

10. A nickel anode comprising carbon about 0.05 to about 2.0%, magnesiumabout 0.05 to about 1.0%, titanium about 0.05 to about 1.0%. siliconabout 0.05 to about 1.0%, cobalt up to about 0.50%, iron up to about0.25%, copper up to about 0.25%, manganese up to about 0.25% and thebalance nickel.

11. A nickel anode comprising carbon about 0.15 to about 1.25%,magnesium about 0.20 to about 0.30%, titanium about 0.15 to about 0.25%,silicon about 0.40 to about 0.70%, cobalt about 0.30 to about 0.40%,iron about 0.10 to about 0.20%, copper about 0.05 to about 0.15%,manganese about 0.05 to about 0.15%, and the balance nickel.

,CLARENCE G. BIEBER. MORTIMER. P. BUCK.

